Chuck



Apr 23g E935, w. D. BURGER 'Er AL.

CHUCK s sheets-sheet 1 Filed Dec. 24, 1931 Ams 23,; m5,

W. D. URGER ET AL 4 CHUCK Filed Dec. 24, 1931 5 Sheets-Sheet 3 Waffe? Vto the heat treatment.l

Eaiented Apr. 23, 1935 UNTEA-Y STAT@ 'A f eteamz,

CHUCK Walter D. Burger, Forest Park,4 and yVictor W.

Peterson, Chicago, lill., assignorsl to Hanniiin Manufacturing Co., Chicago,

of Illinois Appication Becember 24,

s claims. (orare-'119),

This invention relates to chucks, and among other objects aims to provide achuck for holding articles which require a refinishing or trueing operation to render them accurate.

The nature of the invention may be readily understood by reference to illustrative constructions embodying the same andv shown in the accompanying drawings.

lIrrsaid drawings:

chuck, the section being taken on of Fig. 2;

Fig. 2 is a front elevation of the chuck;

Fig. 3 isa plan view looking downV upon one of the circumferentially adjustable jaws;

Fig. 4 is anV axial section through a multiple jaw chuck embodying compensating jaws and taken on the broken line i-d ofFig. 5;

Fig. 5 is a front elevation of the chuck, certain parts having been broken away to permit illustration on a larger scale; Y

Fig. 6 isa plan View similar to that of Fig. 3, of one of the circumferentially.adjustable jaws;

and i Fig. '.7 is an illustration, of a key for effecting a circumferential adjustment of the jaw.

The invention is here shown embodied in a chuck for holding gearsvso thatthe gearbore may be centrally located and the' gear subsequently trued up with a minimum of machining. Gears in common with other circular articles warp somewhat when they cool after being treated to harden or such as those of the teeth. The warping or distortion or may not ce generally regularwhen the gear bore has a key wayv the 'stresses set up on cooling after heating usually cause the here to widen transversely through the key way, giving the pitch line of the gear elliptical shape.

This distortion the plane I-i requires that the gear be trued up, particularly. throughout the 'active portions of the gear teeth surfaces and, of course, at the bore of the gear, if it hasbeen bored previously To minimize the amount of costly re-rnachining of the gear teeth, the gear centered dametrically relative to its pitch line, instead o relatively to the periphery ofthe gears;

and the gear is then bored, remned or ground toV center its bore accurately relatively to the' chucked pitch line. After this only a minimum of machining of the gear cause of the clearances generally allowedy beyond the of the teeth and between the teeth, no machining at these points becomes necessary.V In

reduces 'the trueing up temper their wearingsurfacesv a somewhat l with a space between two gear teeth will be necessary-be- Ill., a corporation i931, sei-nino. 582,922

other words, if the gear bore has previously beeny centered relatively to the pitch line andre-bored or roamed on such center, slight irregularitiesv occurring at the ends andibe'tween' the teeth will not interfere with the proper operation of the` gear; since Athese Ajaws of the teeth do not contactwith any portion -of `a meshing gear. It is merely necessary, therefore, to true up the active portionsof the gear teeth surfaces. Ihis machining to 'a minimum. Onthe other hand, since the gear is not vcenteredronthe periphery of theY gear teeth,r the` irregularities `at Asaid periphery do'not inuence the re-bcringreaming'or grinding operation nor require that the teeth be re-machined relative to` a portion 'of thefgcar, (its periphery) whose Vaccuracygis not essential to a proper operation of vthe gear. n

In Figs. 1, 2V and' 3v are Yillustrated a `three jaw 'chuck 'iii whose jaw structures li, i2 yand I3,r are relatively circumferentially adjustable to adapt them to effect a pitch line'chuckin'g of gears having various numbers of teeth. The gear engaging portions 'of the jaws are provided'with replaceable devices ifi-which enterbetweena pair of gear teeth and engage theteeth'ator very slightly outside the pitch line i5. As here shown, these devices are inthe form of shortcylinders which rest in curved recesses 'i6 in the lower faces of the projecting jaw members Il. The 'gear engaging members i4 arel replaceable by 'others of varying diameter to accommodate the particular geartooth spacing desired so as to secure engagement of the gear teeth substantially `at the pitch line, thereby effecting a chucling of the gear at the pitch line.

The recesses li in which the cylinders i4 rest are slightly larger thanl the cylinders to permit the cylinders to move laterally slightlyto center themselves absolutely between the gear teeth. n

Because of variation of the numbers of gear teeth in various gears, it is necessary to effect a circumferential adjustment of the jaws ifl a .given chuck is to be generally useful'. While this function would not be necessary in a three 'jaw chuck for any gears whose teeth were a whole multiple of three, it is necessary for other gears. For example, with the ten tooth gear, here shown chucked in Fig. 2, the jaws could not-be equally spaced angularly through an angle of.120, since thefcenters of the jaws would not then all register teeth and a chucking of the gear on its pitch line could not be effooted.

In the presentinstance, to provide such relative circumferential adjustment, at least two ofthe- Y base plate I8 may be jaws are made circumferentially adjustable. As here shown the structure of the movable jaw is made movable on the base plate IS of the chuck about the axis of the chuck as a center. Guiding means fol1 this axial movement is here provided in the form of an arcuate groove i S in the face plate in which the projecting ,rib 2G of the jaw housing slides and by which the jaw housing is constrained .to move in an arc of a circle whose center coincides with the axis of the chuck. The jaw housing is clamped in its circumferentially adjusted position by appropriate means suchas bolts and nuts 2| carried by the jaw housing and anchored through slots in the base plate I8 to slidable keys or straps 22 which operate in curved grooves 23 in the back of the base plate l 8.

Preferably, some means is provided for securing the proper angular adjustment of the jaws for a given gear, such for example as a scale 2d on the periphery of the base plate E8 employed in conjunction with a center mark 25 on the jaw housing. The scale may advantageously be in degrees and fractions thereof, and by consultation with an appropriate chart the setting for any desired number of gear teeth may be readily effected. For to give the angular deviation (for a given number of gear teeth) from the normal spacing between jawsif the chuck have, three jaws. Obviously the means by which the angular setting may be determined maybe considerably varied. It is evident that the angular deviation for a given number of gear teeth would be the same for all gear diameters. A radial adjustment of the jaws would, of course, be necessary to accommodate gears of diierent diameters.

Further to facilitate the setting of the movable jaws, a portion of the jaw face adjacent the provided with a series of rack teeth 2B. The jaw may then be moved in a clockwise or counter-clockwise direction by a pinion 2l mounted in the base plate i8 and meshing with the rack teeth. As here shown, the pinion is carried upon a removable key 28 having a pilot projection 29 which enters a hole in the base plate and thus centers the pinion. After an adjustment has been effected by rotating the key, the clamping bolts 2! may be tightened and the jaw held in proper position. For three jaw chucks, it is obviously necessary to set only two of the jaws, the other may remain in a xed position. Y

As here shown, the jaw members I1 are made radially adjustable by adjustably mountingthe same on jaw blocks 3Q. The adjusting means are here shown in the form of intermeshing teeth 3l and 32 on the jaw block and jaw member respectively, together with clamping bolts 33 and 34 which clamp the jaw member in radially adjusted position. The clamping bolts are here shown anchored to a strap or key 35 which slides radially in an undercut V,groove 36 in the jaw block. The precise radial adjustment of the jaw men bers I1 to accommodate a gear of given diameter may be eiected with either a gauge corresponding to the pitch diameter of the gear to which all the jaws may be adjusted, or by using the teeth 3! in the jaw block as an index. In the latter case, the teeth in each jaw block being identically spaced relative to the axis or" the chuck, could serve as a scale for loca-ting the jaws equi-distant from the axis of the chuck.

The illustrative chuck is here shown provided With convenient means for actuating the jaws to grip a gear or other article to be held. VThe jaw blocks 38 are here shown radially slidable in example, the chart may be designed undercut grooves 37 in the jaw housing and the body oi the jaw blocks within the grooves is shaped to conform exactly to the cross section of the groove to be snugly slidable therein and iereby avoid any lateral play. The jaw blocks are operated in this instance by levers 3S in the form of bell cranks pivoted at S9 within the movable housing. It will be und rstood that one lever is employed for each jaw. The short arm of each lever operates in a recess 4i inthe back of the jaw thereby to move it radially. The longer arms 652 o1 the levers are operated by a slidable actuating bar and are shown connected therewith by a slidabie plunger iii in whose circumferential grooves i5 thev ends of the arms seat. Thus, longitudinal movement of the rod 3 causes the levers to move the jaws in or out simultaneously by an equal amount.

The actuating bar 43 may be controlled by any appropriate means such as air cylinders commonly in use for that purpose. The amount of movement effected by actuation of the levers need,l of course, be only a small amount sucient to permit the release and remo-val of a chucked gear, since the adjustment of the jaws for varying iameters ci gears is effected other adjusting means above described. It will be understood.

that upon the circumferential movement of a jaw and its housing, the end of the lever arm d2 will move similarly in the groove 45 of the operating plunger. l

After a gear is chucked on the pitch line, its bore is rerlnished in an appropriate way such as by roaming, to provide a true bore centrally located respecting the pitch 1line which is the basic or controlling factor of the gear. Thereupon, the gearmay be mounted upon the trued bore and the active faces of the gear teeth may be trued up by a minimum of nishing work. As already stated, it will not be necessary to true up either the periphery of the gear or the dedendum at the rootl of the teeth since neither the latter surfaces nor the ends of the gear teeth contact in actual use. Thus a gear may be restored to its correct outline and true form with a minimum or mashining work.

In Figs. 4, 5 and 6 is illustrated a multiple jaw gear-four jaws in this case being shown, in which the respective pairs of opposite jaws are compensated.

As in the three jaw chuck above described, the jaw housings 46 are made circumferentially adjustable relative to the base plate 4l of the chuck. In the present instance, the jaw housings are provided with T headed bolts 48 which operate within arcuate undercut grooves 43 in the base plate. Arcuate guiding keys 50 and 5I carried by the jaw housing androperating in curved, closely tting grooves in the base plate, serve to constrain the axial movements of the jaw housings to a true circle whose center corresponds with the axis of the chuck. Clamping nuts 52 on the T headed bolts 48 serve to clamp the jaw housings in adjusted position.l

As with the three jaw chuck, circumferential '-,r

movements of the jaw housings may conveniently beeieoted by an adjusting pinion mounted in a recess 54 in the periphery oi the chuck housing and meshing with a series of rack teeth VE5 in the inner face of each chuck housing. By mounting the pinion on a key such as shown in Fig. 7, the aforesaid movement may easily be eiected.

Associated with each jaw housing may be an adjusting scale such as shown in Fig. `3 in conaxial movement.

kthe jaws would be required in all cases where the number of gear teeth `was not a whole multiple of four. l f

The jaw members Sie are made radially adjustable in a manner similar to the three kjaw chuck. Each jaw housing is provided with a T-shapedradial groove El within which a key or strap 55 slides. Clamping bolts 5S and Eil pass through the jaw members 56 andV thread into the key 5S. The rear face of the jaw members is provided with a guide rib fil which snugly slides within the groove 5l to prevent lateralplay. The adjacent faces of the jaw memberv 5S and the jaw housing are provided with meshing teeth ft2 and 53 which serve not only to maintain theadjustment of the jaw against any radial movement, but serve as a means for locating theA jaws equiedistant fromV the axis of the chuck. The teeth here shown function similarly to the three jaw chuck above described, but are somewhat square in outline,'whic`n in larger chucks may be more easily machined. To release ajaw for adjustment, it is necessary merely to release the clamping screws 51% and 6e sufficiently to permit the teeth 62 and 53 to clear.

rllhe jaw members 55 are provided with a gear engaging pad 236i somewhat diierent in section than that of the cylinder le shown in connection with the three jaw chuck, although the latter form of gear engaging member might beemployed. The jaw pad comprises a plate having a projecting rib t5 which extends between a pair of gear teeth and is designed to engage them at their pitch line. For diierent gear teeth spacings a diierent pad is employed. At the ends of the rib 65 are stops 56 spaced apart a distance equivalent to the width of the gear face, which serve to hold the gear against the possibility of The jaw' pads are held to the jaw member by a screw Sl which operates in a somewhat larger yhole @il than necessary merely to receive the bolt, in order to provide a'slight tangential play to permit the rib 65 to seat itself accurately between a pair of gear teeth. j

The jaw members here shown aredesigned-to chuck gears of larger diameter; but for chucking smaller gears these may be replaced by a different set of jaw members in .which the jaw face is located nearer the center relative to the series of teeth t2 and 53 on the jaw housing and jaw members.

Clamping movement of the jaws is here efected by making the jaw blocks d, which carry the jaw members, slidable radiallywithin the jaw housings t. As here shown, the housings are provided with undercut grooved guideways 'lil and the jaw blocks have a correspondingsection to have a snug sliding t within the guideway.

Opposite jaw blocks are controlled levers li pivoted at l2 within the respective jaw housings. The shortV lever arms i3 operatively engage recesses 'E45 in the back of the jaw blocks 59 and are actuated by the longer operating arms i5.V The other pair of jaws, i. e., those located at v9W from the first pair is controlled by levers 1S pivoted at il within the respective jaw housings. The short lever arms 'i8 operatively engageL recesses le in the rear faces of the jaw blocks and are operated by the longer arms 85. Arms 'l5 and Si] of the respective pairs of levers are connected to the actuating bar 8l in such a way as to have compensating movements, the effect of which is to permit one pair of jaws to the inner arms Sl n jections e! on the collar SS.

by opposite Ying feature ofthe chuck not moveinwardly after the movement ofthe other pair ofr jaws hasbeen arrested by engagement with. the-article to be checked. Such operation would occur upon the chucking oran article having unequal chucking diameters, as for example, a slightly elliptical shape; one pair oijaws would engage'the article such asa gear at the long diameter ot the ellipse before the other pair of jaws would engage it-a-t its short diameter. If no compensation ofV this character' were provided, the pair of jaws opposite the small diameter of ellipse would be inactive since their clamping movement .would be arrested when the iirst pair gripped the gear at its large diameter.

Ther aforesaid compensating movement is eifected interconnecting the levers ley and Ell. The interconnecting devices are here shown in the formel levers pivotedat 33 within the plunger 84 connected to the end of the actuating bar Si. Av plurality of 'diametrically opposed levers 32 are preferably employed so as t0 avoit any binding of the parts. The outer ends 85 of the levers in this casev operatively engage in ree cesses in the collar or sleeve 36 which actuate the lever arms i5 of the vone pair of jaws. The of the levers operatively engage recesses 8S in the plunger Se which actuates the lever arms Sii controlling the other pair of jaws. .Y

Topermit the levers 'H and it to be located in substantially the same plane, the plunger 89 is recessed at points 9@ opposite the lever arms 'l so as to receive the forwardly extending pro- This avoids increasingA the thickness of the chuck which would be necessary if the bars of levers ll and T8 were not located in the same plane.

It will be evident that the levers 52 permit relative movement between the collar 86 and the plunger Sil, thus permitting movement of one pair of jaws independently of the other pair. Hence, when force is applied by the bar 8! to levers 82, the jaws will be closed simultaneously until one pair .of opposite jaws meets resistance, i. e., when it engages the article to be chucked. This arrests the movement of one end of the levers 82 but does not arrest movement as a whole since the lever 82 will then turn on its pivot and continue to operate the other pairof jaws until they also engage the article to be chucked. The length of the levers 82 is designed to be such as to provide adequatercompensating movement.

In ordinary cases, this compensating movement Compensating movement of this character isy desirable for chucks havingr oppesitely located pairs of jaws, although, of course, it may be embodied in other types of chucks. lThe compensatonly improves the clamping grip upon an article which does not have equal chuclring radii, but renders it possible to locate the center of the article more nearly centrally of theaxis o the chuck.

Obviously the invention is not limited to the details of the illustrative constructions herein shown and described since these may be variously modified. Moreover, it is not indispensable that all features of the invention be used conjointly since various features may advantageously be employed in different combinations and subcoinbinations. p

Having described our invention, We claim:

l. A chuck of tfne character described comprising in corri lnation a chuck body having a plurality of :laws mounted thereon and movable about the chuck axis, a rack and pinion at the meeting' faces of tbe movable jaws and chuck body for moving the former about the chuck axis, and clamping means for clamping the jaws against the chuck body.

2. A chuck oi the character described comprising in combination a chuck body, a plurality of pairs of opposite radially movable chuck jaws, means for mounting said javvs on said body so as to be movable circuinierentially thereon, levers operatively connected with the respective pairs of jaws for moving the same radially to engage and disengage an article, an actuating bar for operating said levers, and a compensating device connecting said bar to said levers to permit one pair of jaws to move toward an article after it has been engaged by another pair of jaws.

3. In apparatus of the character described the combination comprising a chuck having a plurality of pairs of jaws, a pair of concentric sleeves which; are independently and longitudinally movable connected with the respective pairs of jaws for moving the latter, a lever between and engaging said sleeves with. its respective ends, and an actuating bar for applying pov er to said sleeves and connected at the fulcrurn of said lever to transmit force thereto for moving said jaws, said lever being adapted to rock relative to said bar to allow said pairs of javvs independent compensating movement to grip a piece of Work vvliose outer surface is eccentric.

WALTER D. BURGER. VICTOR W. PETERSON. 

